SSDs Overcome Write Endurance With Hot Technology

Solid-state disks (SSDs) face the challenge of write endurance failures when used for disk storage in the data center. Heat may solve the problem.

If you ask most systems administrators about which type of disk storage they would most like to use in their data centers, you probably would get an answer similar to: "I'd like to use SSDs, but I'm concerned that they may suffer from 'write endurance' failures and therefore are not reliable enough."

In some ways, the issue of solid-state disk write endurance is overstated. Today's desktop, laptop, and standalone server SSDs have failure rates that mean they will last almost as long as they are considered useful. But in data center situations, many applications and databases issue read/write calls at a higher frequency, compared to desktop application usage.

That is why there is still cause for concern when SSDs are discussed as a replacement for hard disk storage in the data center. Fortunately, there is a new technology on the horizon that can rejuvenate flash storage as it ages, and therefore eliminate a major concern relating to SSDs.

Flash memory is based on rows and rows of cells that contain two transistors separated by a thin layer of oxide. Depending on the type of charge given, each cell has the ability to store either a 1 or 0 in binary code. When it is determined that the cell is to be erased, an even higher electrical charge is sent to the targeted cells in order to chase the electrons out that represent the binary digits. It's this higher-voltage charge that slowly damages the cells over time to the point where they eventually stop their ability to store data.

With current production SSDs, it's impossible to revitalize them once they've gotten to the point where they no longer respond to calls to create 1s and 0s. But a new technology that is currently under development has the ability to both detect and repair degraded flash cells so they can operate as if they were new again.

As I mentioned earlier, the main culprit involved in wearing out SSD cells is the higher-voltage applied to the cell to erase it. Curiously enough, Macronix has figured out that applying even more power, enough to heat the cells to 800 degrees Celsius, is needed to bring the cells back to life. Essentially, the technique bakes the flash back into a new and operational state. Researchers note that the heating process only takes a few milliseconds and therefore should not add significant power requirement to systems.

If we can finally eliminate the write endurance debate that still looms over SSDs in the data center, they become significantly more attractive to IT administrators. And if SSD prices continue to decline, this would almost certainly signal the end of traditional spinning platter hard disks.